Conduit elbow and method of making it



mm. 2%, W49 J. P. MURDOCH 2,491,757

CONDUIT ELBOW AND METHOD OF MAKING IT Filed Feb. 21, 1944 4 Sheets-Sheet l Jkrafjlfaga op ec. w, 1949 I J. P. MURDOCH 2,491,757

col qnul'r ELBOW AND, METHOD 0} MAKING IT Filed Feb. 21, 1944 4 S he 'ets-SH eer, 2

Dec. 2a, 1949 J. P. MILJRDOCH 2,491,757

CONDUIT ELBOW AND METHOD OF MAKING IT Filed Feb. 21, 1944 4 Sheets-Sheet a 4%.. w, 4944 J. P. MURDOCH 4 9 CQNDUIT ELBOW AND METHOD OF MAKING IT Filed Feb. 21, 1944 4 Sheets-Sheet 4 Patented Dec. 20, 1949 lTED STATES PATENT OFFICE CONDUIT ELBOW AND METHOD OF MAKING IT 3 Claims.

My invention relates to conduits for passage of fluids such as air in distributing systems and to the methods of constructing the conduits.

The main purpose of my invention is to flange the edges of conduit elbow cheeks inwardly toward each other and to fasten a cover sheet known as a wrapper or heel to the outsides of the flanges, facing the flanges inwardly instead of outwardly as in the ordinary conduit flange connections. The invention can be applied to straight conduit sections also.

A further purpose is to form a conduit elbow of checks having the edges at their larger radii turned inwardly toward each other and heels stitched to the inturned edges and following the contour of the outer curves of the elbows. The joints are desirably gasketed and are stitched through the gaskets.

A further purpose is to provide for insertion of an anvil between a flat flange or a cylindrical flange and a cover plate or wrapper which is being fastened to the flange. On curved (cylindrical) flanges such as elbows, the anvil and its support may be inserted from the lateral between unattached tangential part of a wrapper sheet (or heel) and the curve of the flange, or from the end between the cheeks.

Further purposes will appear in the specifications and in the claims.

My invention relates to the methods involved and also to the products which are constructed.

I prefer to illustrate my invention by two main forms only, selecting forms which are practical, effective and inexpensive and which, at the same time, well illustrate the principles of my invention.

In the drawings Figure 1 is a fragmentary perspective view showing one form of my invention.

Figure 2 is a perspective view corresponding generally to Figure 1 but omitting the elbow which is under construction.

Figure 3 is a perspective view showing a single stitcher unit only as compared with the opposite counterpart pair of units in Figure 2.

Figure 4 is a fragmentary top-plan view showing one of the joints under construction.

Figure 5 is a fragmentary side elevation showing structure seen in Figure 4.

Figure 6 is a fragmentary section taken on lines 6-6 of Figure 4.

Figure '7 is a top-plan view partly broken away of an anvil with its anvil support.

Figure 8 is a side elevation of Figure 7.

Figure 9 is a perspective showing the cheeks and throat of an elbow with a wrapper sheet spaced from them and which is to be applied to them.

Figure 10 is a perspective of a straight conduit which is under construction.

Figure 11 is a. fragmentary section of Figure 6 taken on line ll-ll but to a different scale, through the heel or wrapper, the flange and that portion of the yoke radially outside of but in line with the slot.

Figure 12 is a perspective View showing a second form of the invention.

Figures 13 and 14 are top plan views of variant structures which may be used in Figure 12.

Figures 15 and 16 are side elevations of the structures of I3 and I I in position for use.

Figure 17 is an enlarged section of Figure 13 taken on the line "-41.

Notwithstanding that my invention is applicable to the manufacture of straight conduits (such as are seen in Figure 10) as distinguished from conduit elbows, its greatest need as well as its greatest utility lies in the manufacture of elbows, and for that reason it will be described primarily in connection with the elbows.

Sheet metal parts for many years have been fastened together by what are termed stitching machines, which bend and cut continuous wire into staples whose ends are passed through the sheet metal and are turned (clinched) on the under sides of the seams, much in the way that staples are passed through sheets of paper and the staple ends are turned against the under side of a group in ordinary practice.

Except as the stapling machines used for stitching sheet metal use continuous lengths of wire, making their own staples, and operate upon very much thicker and harder material than the paper stapling machines, there is an analogy between the two stapling operations. Both of them apply the staples by plungers and receive the blows of the plungers upon anvils against which the ends of the staples are driven and are turned to clinch the ends against the under faces of the under sheets of those united.

In Figure 1, (the first form of the invention) the stapling machine is shown at l5, having a stapling head It by which a plunger. l1 carrying the wire I8 is driven down against the upper surface of the upper sheet or plate of two sheets which are to be united. If the metal be thin enough, there may, of course, be more than two sheets, and gasketing material, in sheet form or as a paste or paint may lie between the sheets at the joint.

The plunger pierces the metal and passes the wire ends of the staple through the opening. The free ends of the staple are directed toward each other and up against the under side of the under sheet by a clincher means l9, forming part of an anvil.

The clincher means is located and supported upon the inner part 2B of the outer leg 2i of a loop, U oryoke 22. The outer part'23 f the inner leg Z-t is "attached to the post by. aprop, stud or bracket 26. The anvil may, therefore, be considered as supported through the bend or base 27 of the loop U or yoke. The post 25 carries also the stitcher head.

The two legs of the yoke are separated by a" space 23 which is preferably made narrow as a slot or slit 29 opposite the clincher means. A little more slot width is provided elsewhere as at 39 to receive the flange 33.

The spacing between the legs where the flange is straddled by them is kept narrow in order to leave as'jmuch metal as possible at the bend 21 of the yoke'to stiffenthe support of'the anvil. The spacing of the anvil from the adjacent leg wallat 3|"is made just suflicient'to' permit passage of a metal cheek or end wall 32 and properly'to'guide this wall, and the width at 39 need not'be greater than will pass the cheek flange 33. In Figure 10 the wall passed and guided is aside wall 32. There are two cheeks 32.

In other figures than Figure 10 the cheeks are shown 'as'truncated sectors having general triangular shape of the sectors between radial edge wet-115334, 35, outer curved limiting edges 36, usually comprising arcs to these edges as radii, and innercurved limiting edges at 3 1 where the sectors are trunc'ated. Of course, the radii need not 'havethe same centers, the two curves need notbe concentric and the curves need not be arcs.

Inpreparation for the manufacture of'conduit sections such as the elbows seen in Figure 1, the outer curved edge portions are turned transverselyat'SB to form flanges '33 and 33, which because'they generally follow the cur-ves of the sectors, become short cylindrical sections having axial lengths limited by the transverse extent of the'flangingand having circumferential extent measured by the angles between the edges" '34 and '35. 'I he flanges .of'the two cheeks in Figurel are united by astrip' '39 when the flanges face each other'and'ar'e in line. "Upon these flanges 33 and 33'", I mount circumferentially from the outside and stitch step by'step'the cover '39 called a wrapper or heel, which usually is flat at the start but, where initially slightly curved, can be bent as it 'is 'applied' to give the same application effect as if it had been 'flat initially.

TIn bothFigures; 1 and 2, the head nearer the observer is omitted from the illustration though intended to be used When the two seams are to be stitched concurrently and the head I5 is inse'rted by dot and dash only. The operation of the" stitcher is well known and may be performed by any ,of a number of different'stitching machines'upon' the market. It presents no novelty, but of course requires suitable slots, anvils and guides for themetal stitched.

InFigures 1 and 2 stitching machine heads in use-are mounted so as to faceloppositely, toward each other, so that in use, as seen in Figure 1, one"machine"'(the one not illustrated) stitches themeta'l of the'heel near the edge 40 to a flange 33at the same time that the other machine stitches the metal adjacent the farther edge 4| to the other flange 33, the operations being concurrent and there being considerable advantage, as will appear later, in stitching the wrapper or heel to the flanges adjacent both edges of the heel at the same time. It will be apparent, however, that each of the stitching machines is capable of operating entirely independently of the other .to stitch a single--seam,--the second seam being stitched subsequently. Thishasbeen emphasized by inclusion of a single machine only in Figure 3, the machine included being the further one of the two machines intended to operate in Figures 1 and 2.

The loop or yoke may be bent upwardly at some convenient point such as 42 in order that the yoke may be made as short as possible. It is shown in the drawings The stitching machines themselves are viewed by me as conventional machines.

The seams stitched may be direct metalto metal seams, as shown in'Figure 5;ormay be gasketed as at 44'," Figure 10, to avoid leakage of fluid such as air; and the gasketing effect maybe secured as a 'plastic'or'mastic' strip or composition or by paint.

' The upper and lower sheets 39" "and29 may be attached to the flangesby stitching, withor without gasketing.

The cheapness of" my method, as w'ellasthe ease and speed with which it can be performed, and the ease with which gasketing can beeffect'ed constitute considerable advantages of my jinvention.

Initially the cheeks'may be united by a throat 43 which may be held to the cheeks by union with flanges 33 and 33 'corresponding tojfianges 33 and'3ll by stitching or otherwise. Flanges 33 and 33' face each other.

'Using'the cheeks and throat of the'elbow in Figures 1 and 9 as examples; my invention is carried out with either one or two stitching machines as preferred, by placing a'sheet 39 which is intended to form the heel or wrappersuch as seen in'Figure 9 upon the left end or' endsofi'the flangeor flanges33, or33 and 33 in suchpositionthatan initialstitch can be taken. at 545 if a single stitching head onlyisib'eing used-or at 45 and 45' if the two "edges of. the; heel are being stitched concurrentlyFlTh' heelthenextends tangentially with respect .td'th flange. or flanges," leaving a space adjacent each stitch, between the outerfaces of thejflanjges and theflimmediately adjacent inner'su'rface 'of thQhel.

Thetspaceor spaces progressively increaseas the heel'extends to'the right, i. e., as the tangent progressively diverges from-the adjacentccylindrical flange surface ateachfedge, such. as is sh'ownat' dfi'and' l'l iriFigure 1, between the tangentially, arranged heel and the. flange arc orarcs to which J the heel is tangent.

As may be'well illustrated fromltheelbowin Figure 1, where both edges ofthe .wrappenor heeljare attached concurrently, one edge .to one of thetwdfl'a'nges and the other edge v.to the second flange, the first stitches .45. and '45 may be assumed to start at either endf'ofltheheel. They have been assumed to be at'thlefteiui of the heel, into it and into the left ends of: the flanges. They hold the" parts in position.,and

upon the respectiveanvils, the elbowwismmovecl ang'ularly step by step, astitchspacingat atlme While successive stitches ,are put,.in,-}a1l.being placed at thefpos'itionsgof the'anvils.

engine? A number of such steps have been taken and a corresponding number of stitches have been placed in Figure 1. As each pair of stitches is set, one in one flange and the other in the other flange, corresponding short sections of the wrapper or heel, originally preferably plane, are bent to the curvature of the flanges-and are held rigidly in place against the flanges.

As each short section of the length of the wrapper or heel is bent to place, the unattached remaining right hand end of the wrapper or heel extends tangent to the remaining unattached arcs of the flanges.

The spaces between the unattached tangent portion of the heel and the flanges give room for the yokes by which the anvils are supported.

The stitch by stitch insertions of the stitches continue until the entire heel has been attached.

Of course, where a single stitcher only is used one edge only of the heel is attached to one flange only of a single cheek, the operation being otherwise the same except that when the second edge of the heel is attached, the heel is not free to maintain its tangency, nor if needed, to bend slightly away from the arc as when the first edge of the heel is attached.

The heel or wrapper has been treated as a separate cut sheet for the reason only that this is the most convenient way in which to handle it, but it would be possible, of course, to apply the heel or wrapper from a continuous roll of metal and to shear it free from the sheet at any desired point in the operation, for example, after the last stitch has been applied.

The upper surface of the anvil is suitably formed so as to guide the free ends ofthe staple toward each other and clinch them as intended against the under face 48 of the flange.

The form shown in Figure 10 is inserted for the purposes largely of showing packing and of indicating that the spring of the metal of the cover or top (which here takes the place of the heel) may be used to permit bending of the sheet away from the straight flange and thus to provide space for the insertion of the anvil support x yoke when the flange or flanges to which the cover is being stitched is or are plane instead of cylindrical in the face engaged by the cover. A single stitching operation may be performed here also if desired, but as before, there is an advantage in stitching against both flanges at the same time.

The disadvantage of stitching a heel or wrapper-or a cover such as seen in Figure 10--to one flange at a time lies in the fact that after the wrapper, heel or cover has been stitched to one flange only it is not free to separate as a tangent from the arc of the flange as seen in Figure 1, nor free to be bent away from the straight flange in Figure 10.

With one edge united to the first flange along the entire flange length, the wraper or heel, must then be bent along its width from this attached edge. The question of width may then become a serious one, there being enough freedom to bend and still spring back reasonably where a wide wrapper or heel is being applied, but not sufiicient width of metal within which to bend where a narrow heel is being applied. In either event, be the width wide or narrow, securing room for the insertion of the anvil loop is complicated by the necessity to provide for and perhaps force a transverse bending strain which is not required when the heel or wrapper is being applied to both flanges at the same time, as in Figure 1, and

g to provide forbending inza .composite of: two .-d1 rections, longitudinally and transversely in Figure which is located over it, but the character of the support differs from that previously described, that the anvil support reaches under the cover sheet wrapper or heel 39 at a point between the cheeks. It is capable of being applied from either of the open ends in any of the figures, such as the end ts, as distinguished from requiring that supporting yoke shall pass through a free edge, such as one of the tangent edges of Figure 1, and between ,this tangent edge. and the inwardly turned flange 33 or 33.

In Figure 12, two opposite counterpart anvils i9, and 59 and supporting arms 50 and 50,

U (with or without brackets 26) are shown, supported from the post, wholly lacking the yoke construction emphasized in the other figures.

During the stitching operation, the stitchesare all set, one at a time at each anvil position and the two flanges 33 and 33 therefore pass over the anvil from position to position at which a stitch is to be inserted.

There is the same location of the stitches through the flange and the oppositely facing part f the wrapper or conduit cover with the wrapper or heel outside of the flange, and matching its edges 5i, 55! with the outside faces of the cheeks as in the forms previously described, and there is the same progressive step by step closing of the tangent sheet against the flange arc to which it is tangent. There is also the same capacity as before for fastening together two sheets and an intermediate gasket sheet or paste or paint.

The position of supporting post 25', in line with an open end of the conduit section, permits the stitching head with the stitching plunger and all of the active stitching structure to be supported from the same post, reaching out from this post by arm 52 in Figure 13 and by bracket 53 and arm 52, in Figure 14, so that the head l6 and its plunger i! are in position to operate upon intermediate portions of the length of its flange and sheet. The plungers are mounted directly over the anvils H9 or It in each case. The hammer blow of the plunger carrying the stitching wire and applying the stitch thus can be performed in the same manner in the form of Figure 12 as in Figure 1.

Whereas the opposite-counter part anvils'of Figure 12 have their anvil faces ofiset upon left and right extensions respectively in Figure 12 so that these anvils may be inserted from the inside (that is, from positions between the cheeks 32, 32) beneath the flanges 33 and 33 towards the observer at the nearer anvil position and away from the observer at the farther anvil position in Figure 12, because of the necessity of reaching beneath the flange of the cheek in each case, there is no such requirement that the operating head and plunger shall over-hang from the right or from the left. The absence of any such requirement permits construction such as is shown in Figures 13 and 14. It will be noted that in Figures l3 and 14, the head and plunger may be supported upon lateral extensions if desired and such lateral extensions are shown toward the'topof the sheet in Figure 13 and towards the bottomof the sheet in- Figure 14.

It wil1be seen that the supporting larmholding 'thestit'ching head and plunger may be out of line, -'vertically with the anvil arm as in Figure 13 or may be'su-bstantially in a verticalline withwthe anvil arm, as in Figurel l. 'The operation will be substantially thesame as in the previous'figures,

but there will be no need-for any of the support- '-ing parts entering the tangent space shown in Figure lat 46.

Having thus described my invention what I claim as new and desire to'secure by'Letters Pat- I ent is 1. 'The'method of making a conduit elbow from sheet metal, by assembling a throat, cheeks-of sector shape and heel, using a stapling machine and anvil, which comprises flanging the cheeks laterally from the metal of their outer circumferences, uniting the cheeks by the throat, with their flanges facing towards each other and in axial line, and stapling the heel to the flanges against the anvil, step'by step,-by stitches beginning at one flange end and one end of the heel, progressivel taking up the radial distance between the arc of the flange and the adjacent tangentposition of the heel by the successive stitches.

2. The method of making a conduit elbow'from sheet metal, by assembling a throat, cheeks of sector shape and heel, which comprises fianging "the cheeks laterally about the arcs of their outer circumferences, holding the cheeks in spaced relation by the throat, with their flanges facing towards each other and in axial line, and stapling the heel to the flanges while supporting the flange locally from the inside, step by step by stitching beginning with the first stitch at one end of-a flange and one end of the heel, holding theheel Y tangent to the flange and progressively stitching the heel to the flange, each stitch pulling the unattached tangent portion of the heel against the unattached arc of the flange and supporting the 'blow of 'thestitch against the inside of 'the flange throughthespace between the unattached'flange and: the unattached portion of the heel.

3. The method of making a conduit section from side plates having flanges attheir outer edges an-d cover plates adapted to be securedto the flanges, using stitching anvils, which consists in stitching one cover plate to' the outer faces of one'flange of each of the two side plates-with the flanges'facing each other, holding the plates in separated position by this first cover :plate with the-second flanges of the two side plates facing each other, placing the second cover plate "against the-outside faces of the two flanges at one-end 0f the cover plate, stitching the cover plate at this end to each of the two flanges While supporting-the flanges from below, successively applying .stitches through the cover plate and"fianges adjacent those last placed while deflecting the cover plate from the'flanges to give room-for support of the flanges at the point of stitching-each stitch in. turn pressing down a section of the cover plate against. a flange and supporting the flanges by the anvils through the spaces provided by the deflecticnwhile the stitches are applied.

JOHN P. MURDOCH.

REFERENCES CITED The-following references are of record in the file of this patent:

UNITED STATES PATENTS 

